Tape indicator and control switch



Dec. 20, 1960 H. M. PASSMAN TAPE INDICATOR AND CONTROL SWITCH Filed April 10, 1959 Cw. INDEIE IN VEN TOR.

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United States Patent Oflfice p 2,965,727 Patented Dec. 20, 1960 TAPE INDICATOR AND CONTROL SWITCH Harry M. Passman, Cedar Rapids, Iowa, assignor to Collrns Radio Company, Cedar Rapids, Iowa, 21 corporation of Iowa Filed Apr. 10, 1959, Ser. No. 805,604

2 Claims. (Cl. 200-46) This invention pertains to electrical switching and indicating devices and particularly to switching devices in which a conductive endless belt or tape has both means for controlling switching and display means for indicating respective positions of the switching means.

The control device of the present invention is applicable to binary control systems in which any selected ones of several control conductors are to be connected to a particular marking circuit while the remaining conductors are always interconnected. Also at times the interconnected conductors as a group are connected to and then disconnected from the marking circuit. Such systems require substantially fewer conductors between a control station and a controlled station than systems that utilize a simple switching circuit that connect the conductors one at a time. Shaft positioning control systems that use binary input information and which economize on the number of interconnecting control conductors are described in United States Patent 2,476,673 entitled Shaft Positioning Control System and issued to R. W. May et al. on July 19, 1949.

Usually control Systems such as described in the May et al. patent use rotary wafer switches and separate indicator dials. Especially when a large number of switching positions are to be used, the switches and indicators acquire more panel space than that wh'ch is readily available in many equipment installations. The combined switching and indicating device as described herein provides the compactness and the clear visual indication that are desirable in many applications and particularly desirable in aircraft radio communications.

Accordingly the indicating and binary switching device of this invention comprises a thin conductive strip or belt mounted adjacent a conductive member or roller, said strip being insulated from said roller and having openings arranged in rows and spaced within the rows according to coded information and contacts mounted to bear against said strip opposite said member, each of said contacts in response to movement of said strip in the direction of said rows at times being connected to one electrical circuit as the contact bears against said strip and being connected to another electrical circuit as the respective contact enters one of said openings and contacts said adjacent members.

An object of the present invention is to provide a compact control unit that has many switching positions each of which is clearly indicated by a separate visual character.

A feature of the invention is the arrangement of a movable endless tape for displaying positional characters and for applying binary coded electrical conditions to remote control conductors.

The following description and the appended claims may be. more readily understood with reference to the accompanying drawings, in which:

Figure l is a simplified schematic diagram of a shaft positioning system to which the instant switching and indicating device is applicable;

Figure 2 is an oblique view of the switching and indicating device of this invention with a portion of the case cut away;

Figure 3 is an oblique view of the indicating and switching device of this invention with the outer case removed;

Figure 4 is a sectional view of one of the rollers and the tape of Figure 3 taken on the line 44; and

Figure 5 is a cross-sectional view of the roller and tape and an associated contact taken on the line 5 -5 of Figure 4.

The indicating and switching device described herein comprises an endless tape or belt that is fabricated of conductive material and that has accurately positioned coded openings. The tape is mounted on two parallel rotatable rollers spaced apart to receive the tape. One of these rollers is for support only and is insulated from its mounting chassis to prevent application of a continuous ground to the tape. The other roller comprises a conductive cylinder which has on its cylindrical surface thin insulating material to insulate the tape from the cylinder. Spring contacts that are arranged in a row transverse the conductive tape and adjacent to the conductive cylinder are connected to separate control conductors and are disposed to bear inwardly against the tape. Openings on the tape that are spaced according to the desired coded information are moved under the contacts to control either the position of the tape or the position of a remote shaft. The openings in the tape are arranged in rows that are spaced according to the spacing of the contacts so that when the rotors are rotated to move the tape longitudinally to any one of a large number of equally spaced positions, each of the spring contacts either bears against the tape in its newly selected position to induce an electrical marking that has been placed on the tape or enters an oppositely d'sposed opening for contacting the conductive cylinder for inducing into the contact the electrical marking that has been placed on the cylinder.

A remote control system of the type that utilizes a binary control system similar to that described in the May et al. patent supra is shown in Figure l. The position selector switch that is represented for simplicity at the control station as a group of single-pole singlethrow switches 11, may be operated to connect the six conductors of control cable 14 in any desired combination to the grounded conductor 12 or to the ungrounded conductor 13. The conductors of cable 14 terminate at the controlled station in a group of switches 15 that are arranged similar to the switches in the switch group 1 1. When the position of all of the switches 15 correspond to the positions of the switches in group 11, a remote shaft or indicator is in a position that has been selected by operation of switches 11.

When switch positions do not correspond, the control relay 36 is operated to close the circuit of motor 16. The motor operates to position a shaft to which switches 15 are coupled until the switches are in corresponding positions. Commonly the switching elements which have been represented simply as groups of switches 11 and '15 are wafer switches that have the conductors of cable 14 connected to peripheral contacts and that have rotor disks which engage these contacts. The rotor disks have slots and contacting portions arranged so that the disks maybe rotated for applying two states of electrica condition selectively to control conductors 14 in any desired combination.

The switching portion of the switching and indicating device of this invention can be readily substituted forthe previously used wafer switches represented by switches 15 of Figure 1. The device has visual positional charindicating the position that has been selected at the remote control station. Each of the switch arms of the group of switches corresponds to one of the spring contacts of the contact assembly 17 of Figure 3. When the spring contacts of assembly 17 bear against the tape their positions correspond to the positions shown in Figure 1 for arms 1512-151. When the tape 18 has been positioned so that a spring contact passes through the tape and contacts onlythe cylinder 19, the position,

of the spring contact corresponds to the position shown in Figure 1 for switch arm 15a.

A compact design of the instant switching. and indicating device is shown in Figure 2. The tape 18 and its associated rollers are mounted in a rectangular housing 20 thathas minimum height. The characters on the tape are viewed one at a time through the window 21 in the front of the housing and the connections to the spring contacts are made through cable 18 that is attached through a removable connector at the rear of the unit.

As shown in Figure 3, tape 18 is mounted on rollers 22 and 23 that are rotatably mounted on parallel axes by mounting brackets 24 and 25 respectively. Roller 23' is a supporting roller only but must insulate the tape 18 from ground. If the mounting base is fabricated from insulating material, the roller can be either conductive or nonconductive. However, if the roller is mounted on a conductive material, it must be either fabricated from nonconductive material or have its outer cylindrical wall coated with insulating material.

Roller 22 comprises a conductive cylinder 19 that is coated with an insulating material 26. A gold plated, brass cylinder that has a coating of one of the fluorcarbon resins functions satisfactorily. Insulating material of polytetrafiuorethylene marketed under the trade name Teflon by the Du Pont Company can be sprayed onto the cylinder and baked to provide a good insulating coating. The coating is removed from the surface of the cylinder as required to provide circumferential conducting paths 30, Figures 3 and 4, below each of the spring contacts of contact assembly 17. A plurality of sprocket pins 27 that are spaced about t e circumference of cylinder 19 engage a row of sprocket perforations 28 that are disposed in a row on the tape.

The operation of the tape 18 in controlling the spring contacts is clearly shown in a longitudinal cross-se;tional view of roller 22 in Figure 4. The insulating coating has been removed from the roler along circumferential lines 30 that are directly beneath the spring contacts 17a-17f. Contacts 17a and 170, for exam'"le are shown bearing against the tape while alternate contacts, such as contacts 17b have entered respective openings and are in contact with the conductive cylinder 19. No openings have been provided for common contact 17g for this contact continually bears against tape 18 regardlzss of the position of roller 22 and thereby o ovdes a continuous circuit between the tape and a motor control circuit. The shape of a contact 17 is shown in de.ail in Figure 5 and shows that when roller 22 is centered in one of its predetermined positions that the contact, when it is opposite an opening, does not contact the tape but contacts only the conducting cylinder 19. A com on contact 39 is mounted to bear against cylinder 26 for all positions of roller 22.

With reference to Figure 3, springcontact 17g is connected to a motor control circuit 32 for controlling the operation of motor 33. Motor 33 is connected through Geneva gear coupling 34 to the axial mounting shaft 35 of roller 22. The Geneva gear coupling imparts an intermittent rotation to the roller 22 so that the roller and the ribbon, which is driven. by sprocket pins 27, stops at each successive position. When the ribbon is momentarily stopped, the openings 29 of tape 18 are beneath the respective spring contacts and a corresponding character that appears on the tape is stopped. in front of the window 21 of Figure. 2,. The. motor ceases to operate 4 when the openings beneath the contacts correspond to the selected position.

With reference to Figure I, assume that the position selector switch 11 has been operated as shown so that only conductor 14a of control cable 14 is connected directly to the grounded conductor 12. Providing the seeking switch as represented by the group of switches 15 has not been. operated yet to a correspondingposition, a circuit for operatingrelay 36 is completed through the switches. ing. device of Figure 3, the operating circuit for .relay 36 is not opened until the spring contact 17athat corresponds to switching arm 15a is positioned over a respective opening and each of the other five spring contacts 1711-17 bears against the. tape. 'While contact 17a which corresponds to switch arm 15a still bears against the tape, it is obvious that a circuit is completed from ground. through source of voltage 37, winding of relay 36, spring contact 17g, conductive tape 1'8,.switch 'arm 15a which corresponds to contact 17a, conductor ,14a, switch arm 11a to grounded conductor 12. It is obvious that the motor will continue to run at least until the contact 17a encounters an opening so that it is disconnected from the tape and is connected to grounded cylinder 19. V

Moreover, the motor will continue to operate if any of the other spring contacts, for example 17] which corresponds to switch arm 15 is connected to the grounded cylinder 19 rather than to the tape. The circuit can then be traced from ground through source of voltage 37, winding of relay 36, spring contact 17g, throughany' of the contacts that are then connected to the tape, through its corresponding conductor of control cable 14, conductor 13, contact 11 contact 15], which we have assumed to be connected to cylinder 19, and to ground.

Likewise, with reference to Figure 1', relay 36 will be maintained operative for closing contacts 31 which completes the operating circuit for motor 16 until all the switches 1511-15 are in posit'ons corresponding to the respectively connected switches 11a11f. Also with reference to Figure 3, motor 33 will be operated until tape 18 has been properly positioned so that spring contacts 17a-17f encounter electrical conditions corresponding to the grounded and ungrounded electrical conditions that have been appl ed to the control conductors by the remote control selector switch.

The switching and indicating device of this invention may be applied to shaft positioning systems in various ways obvious to those skilled in the art. For example, n certain types of equipment a sending device is operated to appl different combinations of grounded and ungrounded circuits successively in a predetermi ed order automatically to the spring contacts 17a1 7f of Figure 3 for continuously operating motor 33. Since the Geneva gear coupling 34 provides required intermittent operat'on of tape 18, the characters or indicating members on the tape mav be readily read through window 21. At the s"me time that the grounded and ungrounded combinations are being applied to contacts 17a-17f. the same combinat'ons are be'ng app ied to ot er remote equpment. When the desired indicating figure appears in window 21, the operator stops the sending device so that the remote equipment is maintained in a selected condition. In another arrangement the sw'tching device pf F'gure 3 mav be used as a sendingdevice 'at the control station. For example. a manual control may be coupled to roller 22 and contacts 17a-17f ma be connected in p ace of switch arms 11a17f of Figure 'l. in still another arrangement the switchi g and indicating device ma be located at the controlle e ioment so that roller 22 may be connected to a shaft that is'to'be positioned such as tuning shaft 38 of Figurel.

Although this invention has been described with reference to a single embodiment, the switching and in- More particularly with reference to the switch? v in dicating device of this invention may be changed in obvious ways by those skilled in the art and connected as required for difierent applications and still would be within the spirit and scope of the following claims.

What is claimed is:

1. An indicating and switching device comprising a conductive tape, said tape having character indicia for indicating the position thereof and openings for controlling switching in binary control circuits, a driving roller, means including said roller to support said tape and to advance it longitudinally, a plurality of spring contacts that are to be connected to conductors that transmit positional information in binary form, said contacts being spaced apart transverse said tape adjacent the surface of said roller, said openings in said tape being arranged in longitudinal rows and being spaced within said rows according to a predetermined switching sequence, each of said rows being aligned with a respective one of said contacts, said roller having a conductive cylindrical surface, a thin insulating medium covering the outer portion of said surface other than that opposite said contacts to insulate said tape from said cylinder, means for urging said contacts against said tape toward said conductive cylinder, the ones of said contacts bearing against said tape being electrically interconnected therethrough, the other ones of said contacts passing through said openings in said respective rows to contact said cylinder only, a first common contact mounted to provide continuous contact with said tape, and a second common contact mounted to provide continuous contact with said cylinder.

2. In a remote shaft positioning system having a plurality of remote control conductors that transmit binary positional information, an endless tape that displays positional characters and that also controls binary switching, said positional characters being arranged in a longitudinal row on said tape, means including a rotatably mounted roller for mounting said tape and for advancing said tape longitudinally, said roller having a conductive cylinder, a plurality of spring contacts mounted spaced apart transverse a portion of said tape adjacent said cylinder and mechanically biased to bear against said tape toward said cylinder, certain ones of said contacts being connected to separate ones of said remote control conductors, an insulating medium covering a portion of the outer surface of said cylinder other than portions opposite said contacts to separate said tape slightly apart from said cylinder, said tape having openings arranged in longitudinal rows, each of said rows being aligned with each of said contacts that are connected to said remote control conductors, said means being operable for intermittently repositioning said tape at intervals corresponding to the spacing of successive positional characters on said tape, said openings within said rows being arranged to allow different predetermined ones of said spring contacts at each new position of said tape to pass through said tape and contact only said cylinder, the ones of said contacts bearing against said tape being electrically interconnected, a first common contact mounted to bear continuously against said tape and, therefore, to provide electrical connection to said ones of said contacts that bear against said tape, and a terminal connected to said cylinder for providing connection to said other of said contacts that pass through said openings.

References Cited in the file of this patent UNITED STATES PATENTS 2,734,954 Kidd Feb. 14, 1956 

